IBM TotalStorageFAStT900, User Manual

Page: 64 / 112

Attention: If you are removing both controllers (controller A and controller B) from
the FAStT900 Storage Server, label controllers A and B with the white tape dots that
are included in the rack mounting assembly kit. To prevent data loss, the controllers
must be installed into their original location.
Servicing notes
Consider the following factors when servicing the controllers in the FAStT900
Storage Server:
v
The FAStT900 Storage Server supports two controller CRUs, which attach to
hosts through Fibre Channel connections.
v You can hot swap or replace a failed controller while the FAStT900 Storage
Server is in operation as long as the host has a Fibre Channel connection to the
functioning controller and is in a “passive” or “offline” status in the
storage-management software.
v
If cache mirroring is enabled in redundant controllers and one controller fails, the
second controller assumes processing functions without data loss. However,
some or all data might be lost if cache mirroring is disabled and a failure occurs
before data is written from cache memory to disk.
v
If you replace the controller CRU and still experience problems, the FAStT900
Storage Server might have other defective components or connections. Check
the storage-management software for indications of other component failures.
v When a controller CRU fails, the fault light on the affected controller is lit. For
more information about indicator lights, see “RAID controller indicator lights” on
page 22.
Figure 33. Controller status indicator lights
38
IBM TotalStorageFAStT900 Fibre Channel Storage Server: User’s Guide